Ceramics composite member and method of producing the same

ABSTRACT

A ceramics composite member includes a structure in which a first ceramic member and a second ceramic member are integrated with a joint portion. The joint portion has a texture in which a silicon phase having an average diameter of 0.05 μm or more and 10 μm or less is continuously provided in a network form in interstices of silicon carbide particles having an average particle diameter of 0.1 μm or more and 0.1 mm or less.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromthe prior Japanese Patent Application No. 2006-324306 filed on Nov. 30,2006; the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a ceramics composite member and methodof producing the same.

2. Description of the Related Art

Structural ceramics are used as heat-resistant members andabrasion-resistant members because they excel in environment resistance,heat resistance and abrasion resistance and also have outstandingcharacteristics such as high rigidity, low thermal expansion and lowspecific gravity. Ceramic members such as alumina (Al₂O₃), zirconia(ZrO₂), silicon nitride (Si₃N₄) and silicon carbide (SiC) are beingworked mainly toward practical use for semiconductor-related componentssuch as jigs for semiconductor production equipment and others in theseyears. Besides, the ceramic members are being applied to industrialequipment such as nuclear, gas turbine and other energy equipment parts,structural parts for space, automobile engine parts, heat exchangerparts, pump parts, mechanical seal parts, bearing parts, sliding partsand the like.

The ceramic members are known that they are hardly produced into largeparts and complex-shaped parts because they generally shrink by about20% at the time of sintering. Then, it is attempted to produce largeparts and complex-shaped parts by bonding plural ceramic members. As amethod of bonding the ceramic members, there are known, for example, amethod of bonding them with a brazing material containing active metaland a method of bonding the ceramic members with a brazing materialafter metallizing their surfaces. But, such bonding methods have adisadvantage that the heat resistance and strength of the parts arelimited depending on a metal layer which is present as a bonding layer.

In contrast to the bonding method using the brazing material, there isknown a method of bonding plural ceramic members by utilizing reactionsintering of silicon carbide. Japanese Patent Publication No. HEI5-079630 (KOKOKU) describes a method of bonding a silicon carbide bodyand a porous body of silicon carbide with an organic binder containingsilicon carbide particles. The silicon carbide body and the porous bodyof silicon carbide are overlaid with the organic binder containing thesilicon carbide particles therebetween, and they are impregnated withsilicon melted from the top surface of the porous body of siliconcarbide. The melted silicon impregnated through the pores in the porousbody of silicon carbide and the carbon in the organic binder are reactedto produce the silicon carbide layer (bonding layer) so as to join thesilicon carbide body and the porous body of silicon carbide.

But, the conventional bonding method using the reaction sintering ofsilicon carbide has a disadvantage that applicable component shapes arelimited because the melted silicon impregnates through the pores in theporous body of silicon carbide. It also has a disadvantage that thestrength of the bonded body cannot be enhanced sufficiently because theprocess of producing the silicon carbide in the bonding layer cannot becontrolled. For example, the reaction-sintering layer as the bondinglayer has a microheterogeneous structure, and many pores and coarse freesilicon phases are produced in the reaction-sintering layer. They arecauses to degrade the strength of the bonded body.

Pamphlet of (PCT) International Publication No. WO-A1 2004/007401 andJP-A 2005-022905 (KOKAI) describe a method of bonding plural componentunits including a silicon-silicon carbide composite sintered body via areaction-sintering layer (silicon-silicon carbide composite materiallayer). Here, plural silicon-silicon carbide composite sintered bodies(or shaped bodies containing silicon carbide and carbon) are adheredwith an organic adhesive, and the bonded portion effected with theorganic adhesive is impregnated with melted silicon. And, pluralcomponent units are bonded with the bonding layer which is mainlycomposed of silicon carbide particles which are produced by reacting thecarbon in the organic adhesive with the melted silicon and a freesilicon phase present among them.

The bonding method using the organic adhesive can improve denseness ofthe bonding layer, controllability of the microstructure and the likebecause the free silicon phase is present in a network form in theinterstices of the silicon carbide particles configuring the bondinglayer. Thus, it becomes possible to enhance bonding strength incomparison with the method of impregnating with the melted siliconthrough the pores in the porous body of silicon carbide. But, thegeneration of the silicon carbide particles configuring the bondinglayer based on only the carbon in the organic adhesive has a drawbackthat it is poor in reproducibility of bonding strength.

In other words, the carbon in the organic adhesive involves volumeexpansion when it reacts with the melted silicon, and the siliconcarbide particles produced originating from the initial resin structuretend to aggregate. Therefore, the interstices of the silicon carbideparticles tend to become heterogeneous, and there is a possibility thatthe free silicon phase segregates. The free silicon phase has lessstrength in comparison with the silicon carbide particles, and if thefree silicon phase segregates, the bonding layer tends to have variablestrength. Thus, it is a cause of lowering of the reproducibility of thebonding strength of a bonded part applying the bonding method using theorganic adhesive.

SUMMARY OF THE INVENTION

According to an aspect of the present invention, there are provided aceramics composite member with mechanical properties such as strengthenhanced with a good reproducibility by making a bonding layerhomogeneous and minute, and a method of producing the same.

A ceramics composite member according to an aspect of the inventionincludes: a first ceramic member; a second ceramic member; and a jointportion which couples the first ceramic member and the second ceramicmember and has a texture including silicon carbide particles, which havean average particle diameter of 0.1 μm or more and 0.1 mm or less, and asilicon phase, which is continuously provided in network form ininterstices of the silicon carbide particles and has an average diameterof 0.05 μm or more and 10 μm or less.

A method of producing a ceramics composite member according to an aspectof the invention includes: adhering a first ceramic member and a secondceramic member with an adhesive containing at least silicon carbidepowder and an organic resin; heat-treating a bonding portion based onthe adhesive to carbonize the adhesive; and impregnating the bondingportion with melted silicon to couple the first ceramic member and thesecond ceramic member with a joint portion which is formed byreaction-sintering the bonding portion.

A method of producing a ceramics composite member according to anotheraspect of the invention includes: adhering shaped bodies each containingsilicon carbide powder and carbon powder or the shaped body and aceramics sintered body with an adhesive containing at least siliconcarbide powder and an organic resin; heat-treating a bonding portionbased on the adhesive to carbonize the adhesive; and impregnating theshaped bodies and the bonding portion with melted silicon to couplesilicon-silicon carbide composite sintered bodies which are formed byreaction-sintering the shaped bodies or the silicon-silicon carbidecomposite sintered body and the ceramics sintered body with a jointportion which is formed by reaction-sintering the bonding portion.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a ceramics composite memberaccording to an embodiment.

FIG. 2 is a sectional view showing a magnified structure of the ceramicscomposite member shown in FIG. 1.

FIG. 3 is a sectional view showing a magnified structure of the jointportion of the ceramics composite member shown in FIG. 1.

FIG. 4 is a sectional view showing a state before an impregnation withmelted Si in the joint portion shown in FIG. 3.

FIG. 5 is a sectional view showing a magnified joint portion of theceramics composite member shown in FIG. 1.

FIGS. 6A, 6B, 6C and 6D are sectional views showing a production processof the ceramics composite member according to a first embodiment.

FIGS. 7A, 7B, 7C and 7D are sectional views showing a production processof the ceramics composite member according to a second embodiment.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present invention will be described below withreference to the drawings. FIG. 1 is a perspective view showing astructure of the ceramics composite member according to an embodiment ofthe invention, and FIG. 2 is a sectional view showing a magnified part.A ceramics composite member 1 shown in the drawings includes a firstceramic member 2 and a second ceramic member 3. The first and secondceramic members 2 and 3 are coupled (bonded) via a joint portion 4.

As indicated by the magnified view of FIG. 4, the joint portion 4 has atexture in which a silicon phase (free Si phase) 6 is continuouslyprovided in network form in interstices of silicon carbide particles(SiC particles) 5. Here, the composite member 1 having the two ceramicmembers 2 and 3 coupled is shown, but the number of ceramic membersconfiguring the ceramics composite member 1 is not limited to two. Thenumber of ceramic members may be three or more.

The first and second ceramic members 2 and 3 are not particularlylimited, and the same or different kinds of ceramics sintered bodiesselected from carbide, nitride, oxide, boride, silicide and theircomposites can be applied. Specific examples of the ceramic membersinclude a silicon carbide (SiC) sintered body, a silicon-silicon carbide(Si—SiC) composite sintered body, a silicon nitride (Si₃N₄) sinteredbody, a sialon (Si—Al—O—N) sintered body, an alumina (Al₂O₃) sinteredbody, a zirconia (ZrO₂) sintered body, and their composite sinteredbodies.

The first and second ceramic members 2 and 3 can be selectedappropriately depending on the parts and usage to which the ceramicscomposite member 1 is applied. Especially, the application of thesilicon-silicon carbide composite sintered body and the silicon carbidesintered body having the same material as the joint portion 4 canimprove the strength of the ceramics composite member 1.

The joint portion 4 has the texture in which the free Si phase 6 iscontinuously provided in the network form in the interstices of the SiCparticles 5. The joint portion 4 can be obtained by heat-treating (heattreatment for carbonization by thermally decomposing an organic resin)an adhesive layer containing at least silicon carbide powder and anorganic resin, and impregnating with melted silicon (Si) to performreaction-sintering. The adhesive layer may contain carbon powder. Thejoint portion 4 includes first SiC particles 5 a which are based on thesilicon carbide powder compounded with the adhesive layer and second SiCparticles 5 b which are produced by reacting the melted Si with carbonderived from the carbon powder and the organic resin compounded with theadhesive layer as shown in FIG. 3.

The SiC particles 5 configuring the joint portion 4 are controlled sothat they have an average particle diameter of 0.1 μm or more and 0.1 mmor less as a whole including the first and second SiC particles 5 a, 5b. If the SiC particles 5 have an average particle diameter exceeding0.1 mm, the microstructure of the joint portion 4 becomes heterogeneous,and the free Si phase 6 having less strength than the SiC particles 5tends to be segregated. The strength and toughness of the joint portion4 are degraded. Therefore, the strength of the ceramics composite member1 which has the first ceramic member 2 and the second ceramic member 3joined via the joint portion 4 cannot be expressed satisfactorily.

The strength of the joint portion 4 also lowers when the SiC particles 5have an average particle diameter of less than 0.1 μm. The SiC particles5 having an average particle diameter of less than 0.1 μm tend toaggregate and are hardly dispersed into the adhesive, so that a stablebonding layer is hardly obtained in view of the production process.Therefore, the strength and yield of the ceramics composite member 1become low, and its reliability and endurance are also degraded. It ismore desirable to control so that the SiC particles 5 have an averageparticle diameter of 0.5 to 50 μm. The average particle diameter of theSiC particles 5 is a value determined by mirror-finishing an arbitrarycross section of the joint portion 4, observing its texture through anoptical microscope (metallurgical microscope) or an electron microscope,and performing image processing on a magnified picture of the texture.

The shapes of the first SiC particles 5 a blended as an aggregate andthe second SiC particles 5 b produced by reaction-sintering arecontrolled to have the average particle diameter of the SiC particles 5in a range of 0.1 μm or more and 0.1 mm or less. FIG. 4 shows a state ofthe adhesive layer (porous layer) before the impregnation with themelted Si. Silicon carbide powder 7 has substantially no grain growth inthe melted Si impregnation step. If the first SiC particles 5 a based onthe silicon carbide powder 7 have a particle diameter smaller than thatof the second SiC particles 5 b, it is hard to obtain a homogeneouscomposite texture (composite texture having the free Si phase 6continuously provided in the network form in the interstices of the SiCparticles 5). If the first SiC particles 5 a have a particle diameterexcessively larger than that of the second SiC particles 5 b, the sizeof the free Si phase 6 does not become homogeneous, so that the strengthof the joint portion 4 lowers.

Carbon powder 8 and a carbon component 9 derived from the organic resinexpand in volume when they react with the melted Si to generate SiC (thesecond SiC particles 5 b). Therefore, it is important to control theparticle diameter of the carbon powder 8 to be blended into the adhesivelayer and to control the size of the carbon component 9 to be formed byheat-treating the organic resin considering the particle diameter of thefirst SiC particles 5 a. Especially, it is important to control the sizeof the carbon component 9. If the second SiC particles 5 b have aparticle diameter larger than that of the first SiC particles 5 a, thefree Si phase 6 has a heterogeneous distributed state.

The size of the carbon component 9 derived from the organic resin can beminiaturized by, for example, blending appropriate amounts of thesilicon carbide powder 7 and the carbon powder 8 into the adhesive andcontrolling the heat treatment conditions for carbonization of theorganic resin. Blending of the silicon carbide powder 7 into theadhesive layer makes it possible to have the organic resin uniformly andfinely in the gap among the powder grains. The distributed state of theorganic resin can be further made uniform and fine by blending thecarbon powder 8 into the adhesive layer.

The size of the carbon component 9 can be miniaturized by heat-treatingthe organic resin when the carbon component 9 is formed. Besides, thecarbon component 9 can be suppressed from aggregating. And, the adhesivelayer containing the carbon component 9, the carbon powder 8 and thesilicon carbide powder 7 is impregnated with the melted Si, andreaction-sintering is performed, so that it becomes possible to controlthe average particle diameter of the SiC particles 5 as a whole to fallin a range of 0.1 μm or more and 0.1 mm or less.

The free Si phase 6 is continuously provided in the network form in theinterstices of the SiC particles 5. It is important that the free Siphase 6 has a continuous network structure. If the network structure ofthe free Si phase 6 is separated, the occurrence of a choking phenomenon(phenomenon that the melted Si supply routes are cut to stop thereaction of carbon) is induced to increase a residual carbon amount, andthe strength of the joint portion 4 is lowered. A compact joint portion4 can be obtained by continuously disposing the free Si phase 6 in theinterstices of the SiC particles 5. Besides, the joint portion 4preferably has a porosity of 5% or less. If the joint portion 4 has aporosity exceeding 5%, the strength of the joint portion 4 becomesvariable greatly and the strength of the ceramics composite member 1also becomes variable greatly.

The free Si phase 6 is determined to have an average diameter of 0.05 μmor more and 10 μm or less. The average diameter of the free Si phase 6is equivalent to an average distance among the SiC particles 5. Theaverage diameter of the free Si phase 6 indicates a value determined asfollows. First, the ceramics composite member 1 having the joint portion4 is heated to 1600° C. under reduced pressure to remove free Sicontained in the joint portion 4. It is assumed that the averagediameter of the free Si phase 6 indicates an average value of thediameters determined by a mercury porosimetry assuming that thediameters of fine pores formed by removing the free Si are cylinders.The obtained value agrees with the result obtain by observing thecross-sectional microstructure of the joint portion 4 under ametallurgical microscope or a SEM.

The fact that the free Si phase 6 has a small average diameter meansthat the free Si phase 6 having low strength is miniaturized. It alsomeans that the free Si phase 6 is distributed homogeneously in theinterstices of the SiC particles 5. The interstices of the SiC particles5 is thoroughly filled with the free Si phase 6. The strength of thejoint portion 4 and the ceramics composite member 1 can be improved witha good reproducibility by controlling so that the free Si phase 6 has anaverage diameter of 10 μm or less. If the free Si phase 6 has an averagediameter of less than 0.05 μm, it is hard to keep a continuous networkstructure. Thus, holes and free carbon tend to be formed in the jointportion 4, and the strength of the joint portion 4 becomes variable.

The average diameter of the free Si phase 6 is controlled by optimizingthe particle diameter and the compounding ratio of the silicon carbidepowder 7 and the carbon powder 8 in the adhesive layer which becomes asource for forming the joint portion 4. The silicon carbide powder 7 hassubstantially no grain growth in the melted Si impregnation step. Thecarbon powder 8 and the carbon component 9 present in the interstices ofthe first SiC particles 5 a based on the silicon carbide powder 7 arereacted with the melted Si to homogenize the distributed state of thefree Si phase 6. Besides, the free Si phase 6 is suppressed fromsegregating. Thus, it becomes possible to obtain the free Si phase 6which is fine and uniform.

But, if the silicon carbide powder 7 and the carbon powder 8 are blendedin excessively large amounts into the adhesive, adhesiveness and bondingstrength are degraded. Therefore, it is desirable that the amounts ofthe silicon carbide powder 7 and the carbon powder 8 added to theorganic resin, which is a main constituting material of the adhesive,and also the particle diameters of the silicon carbide powder 7 and thecarbon powder 8 are adjusted appropriately. Thus, it becomes possiblethat the free Si phase 6 is uniformly miniaturized, and the continuousnetwork structure of the free Si phase 6 can be kept stably.

In a case where the SiC particles 5 in the joint portion 4 are producedby only the reaction of the carbon component 9 derived from the organicresin, the carbon component 9 tends to aggregate because of the originalresin structure. Therefore, a choking phenomenon occurs, or the free Siphase 6 becomes nonuniform and its average diameter increases. The freeSi phase 6 has less strength in comparison with the SiC particles 5, sothat the segregation of the free Si phase 6 becomes a cause of thedegradation or variation in strength of the joint portion 4. Blending ofthe silicon carbide powder 7 and the carbon powder 8 into the adhesivesuppresses the carbon component 9 derived from the organic resin fromaggregating, and the miniaturized free Si phase 6 can be obtained.

It is desirable that the content of the free Si phase 6 in the jointportion 4 is in a range of 5 to 85 mass %. If the content of the free Siphase 6 exceeds 85 mass %, the strength of the joint portion 4 and theceramics composite member 1 cannot be improved with a goodreproducibility. If the content of the free Si phase 6 is less than 5 wt%, the network structure is separated, and pores and free carbon tend togenerate. In such a case, the strength of the joint portion 4 isdegraded. The content of the free Si phase 6 is preferably in a range of5 to 75 mass %, and more preferably in a range of 10 to 50 mass %. Thecontent of the free Si phase 6 can be calculated on the basis of thetheoretical density of Si and SiC from the result of image processing onthe texture-observed pictures and the density of the joint portion 4.

The thickness of the joint portion 4 is preferably in a range of 5 μm ormore and 5 mm or less as an average thickness. It is hard to produce thejoint portion 4 having an average thickness of less than 5 μm in view ofa production process, and a portion, where the joint portion 4 isinsufficiently formed, becomes defective, and the strength andreliability of the joint portion 4 degrade, and those of the ceramicscomposite member 1 also degrade. If the average thickness of the jointportion 4 exceeds 5 mm, the joint portion 4 becomes a cause ofdegradation of the strength, and the strength and reliability of theceramics composite member 1 are degraded. It is desirable that theaverage thickness of the joint portion 4 is made thin in such a rangethat a uniform state can be obtained. The joint portion 4 desirably hasan average thickness of 1 mm or less, and more preferably 0.5 mm orless.

The joint portion 4 preferably has a three-layer structure as shown inFIG. 5. The joint portion 4 shown in FIG. 5 has first and second sidelayers 10, 11, which are in contact with the first and second ceramicmembers 2 and 3, and an intermediate layer 12 which is positionedbetween them. The content of the free Si phase 6 in the intermediatelayer 12 is different from those of the first and second side layers 10,11. The content of the free Si phase 6 in the intermediate layer 12 islarger than in the first and second side layers 10, 11. It is desiredthat the intermediate layer 12 has a free Si composition ratio of 10 to85% higher than the first and second side layers 10, 11. The centerlayer 12 has preferably a thickness of 3 μm or more and 3 mm or less.

The first and second side layers 10, 11 contain the free Si phase 6 inan amount smaller than that in the intermediate layer 12. A bondingstrength to the first and second ceramic members 2, 3 can be furtherenhanced by the joint portion 4 having the side layers 10, 11.Therefore, the reliability and endurance of the ceramics compositemember 1 can be improved furthermore. The joint portion 4 having thefirst and second side layers 10, 11 and the intermediate layer 12 can beobtained by controlling the structure of the porous layer mainlycomprising carbon according to the heat treatment conditions and thelike for the adhesive layer. Besides, the adhesion strength of the sidelayers 10, 11 can also be enhanced by increasing the surface roughnessof the adhered surfaces of the first and second ceramic members 2, 3.

The ceramics composite member 1 of this embodiment controls themicrostructure of the joint portion 4 for coupling the first and secondceramic members 2 and 3. Specifically, it controls the average particlediameter of the SiC particles 5 configuring the joint portion 4, and thenetwork structure and the average diameter of the free Si phase 6present in the interstices of the SiC particles 5. Thus, the strength ofthe joint portion 4 can be enhanced with a good reproducibility. Thejoint portion 4 typically has properties such as a Vickers hardness ofHv900 to 2200 and a four-point bending strength of 250 to 1400 MPa. Thefour-point bending strength of the joint portion 4 indicates a valueobtained by measuring the four-point bending strength of the compositemember 1 with the joint portion 4 determined at the center.

The ceramics composite member 1 having the above-described joint portion4 can enhance the mechanical properties such as a strength and the likewith a good reproducibility, so that it can be applied to various typesof members and parts which are required to have high strength.Especially, it contributes greatly to provision of high strength tolarge structures, complex-shaped parts and the like. The ceramicscomposite member 1 can be applied to various types of equipment partsand equipment members such as jigs for semiconductor manufacturingdevices, semiconductor-associated parts (heatsink, dummy wafer, etc.),high-temperature structural members for gas turbines, aerospace andaeronautical structural members, mechanical seal members, brake members,sliding parts, mirror parts, pump parts, heat exchanger parts, chemicalplant component parts and the like, and especially suitably used for theequipment parts and members which are required to have high strength.

Then, an embodiment of a method of producing a ceramics composite memberof the invention will be described. The method of producing the ceramicscomposite member 1 of the invention is classified broadly into a firstmethod for bonding plural ceramics sintered bodies and a second methodfor bonding in a stage that at least one of them is a shaped bodyincluding silicon carbide powder and carbon powder. The first methodwill be described in detail with reference to FIG. 6A through FIG. 6D.

As shown in FIG. 6A, two or more ceramics sintered bodies 21 areprepared. For the ceramics sintered bodies 21, the same or differentkinds of ceramics sintered bodies selected from carbide, nitride, oxide,boride, silicide and their composites are used. Specific examples of theceramics sintered bodies 21 are as described above. Adhered surfaces 21a of the ceramics sintered bodies 21 are preferably subjected to a blasttreatment or an etching treatment to previously increase the surfaceroughness. Thus, adhesiveness of the joint portion 4 formed byimpregnation with the melted Si and the ceramics sintered bodies 21 andalso their bonding strength can be enhanced.

Then, as shown in FIG. 6B, the two ceramics sintered bodies 21 areadhered with an adhesive 22 containing silicon carbide powder and anorganic resin. The adhesive 22 may also contain carbon powder. Theadhesive 22 is present as an adhesive layer between the ceramicssintered bodies 21. The organic resin as an adhesive component of theadhesive 22 is preferably a thermosetting resin such as a phenol resin,a melamine resin, an unsaturated polyester resin, an epoxy resin, apolyurethane resin, a polyimide resin or the like. Thus, the layer shapeof the adhesive 22 before the impregnation with the melted Si can bekept stably, and a filling property and dispersibility of the siliconcarbide powder and the carbon powder in the adhesive 22 can be improved.

The silicon carbide powder contained in the adhesive 22 desirably has anaverage particle diameter of 0.1 to 100 μm. If the silicon carbidepowder has an average particle diameter of less than 0.1 μm, thedistributed state of the silicon carbide powder 7, the carbon powder 8and the carbon component 9 in the porous layer (FIG. 4) formed by theheat treatment of the adhesive 22 tends to become heterogeneous. Thus,the dispersed state of the second SiC particles 5 b and the free Siphase 6 in the joint portion 4 (FIG. 3) formed with the porous layerimpregnated with the melted Si becomes heterogeneous. If the averageparticle diameter of the silicon carbide powder exceeds 100 μm, the sizeof the free Si phase 6 becomes large, and there is a possibility thatthe strength of the joint portion 4 cannot be enhanced sufficiently.

The carbon powder preferably has an average particle diameter of 0.08 to20 μm. If the carbon powder has an average particle diameter of lessthan 0.08 μm, it tends to aggregate, and the distributed states of thesecond SiC particles 5 b and the free Si phase 6 in the joint portion 4(FIG. 3) become heterogeneous. If the average particle diameter of thecarbon powder exceeds 20 μm, a choking phenomenon tends to occur, andthe strength of the joint portion 4 might be degraded. Besides, the freeSi phase 6 has a large average diameter, and the strength of the jointportion 4 is degraded or becomes variable.

It is preferable that the adhesive 22 contains the silicon carbidepowder in a range of 5 to 80 mass % with respect to a total amount ofthe silicon carbide powder and the carbon component derived from thecarbon powder and the organic resin. A mass ratio of the silicon carbidepowder and the carbon component derived from the carbon powder and theorganic resin is preferably determined as SiC:C=5 to 80:95 to 20, andmore preferably SiC:C=10 to 70:90 to 30. If the ratio of the siliconcarbide powder is less than 5 mass %, the distributed state of the SiCparticles 5 and the free Si phase 6 in the joint portion 4 becomesheterogeneous. Meanwhile, if the ratio of the silicon carbide powderexceeds 80 mass %, the porosity of the joint portion 4 increases, andthe strength cannot be expressed satisfactorily. Thus, the ceramicssintered bodies 21, 22 are mutually adhered with the adhesive 22.

Then, as shown in FIG. 6C, the adhesive layer 22 is carbonized byheat-treating, and the adhesive layer 22 becomes a porous layer 23accordingly. In other words, the organic resin is carbonized bythermally decomposing, and the adhesive layer 22 is changed to a porousbody. The porous layer 23 functions as a preliminary joint portion. Theheat treatment to change the adhesive layer 22 to the porous body ispreferably performed in vacuum or an inert gas atmosphere at atemperature in a range of 400 to 2000° C.

It is desirable that the porous layer 23 has a porosity of 20 to 80%. Ifthe porosity of the porous layer 23 is less than 20%, the supply routesfor the melted Si are cut to cause a choking phenomenon, and a residualcarbon amount of the joint portion 4 increases, or the production of thesilicon carbide from carbon accompanies a volume expansion to causecracks easily. If the porosity of the porous layer 23 exceeds 80%, theamount of the free Si phase increases. Such phenomena become the causeof degradation of the strength of the joint portion 4. Besides, if theporosity is excessively high, the preliminary joint portion (porouslayer) 23 before the impregnation with the melted Si tends to havecracks or the like, and the production yield and strength of theceramics composite member 1 are degraded.

Then, the porous layer 23 as the preliminary joint portion is heated toa temperature of the melting point or more of Si, and the porous layer23 in the heated state is impregnated with the melted Si. The melted Siimpregnation step heats the porous layer 23 as the preliminary jointportion to, for example, a temperature of 1400° C. or more andimpregnates it with the melted Si in vacuum or in an inert atmosphere.By the melted Si impregnation step, the porous layer 23 as thepreliminary joint portion is subjected to reaction-sintering to form thejoint portion 4. In other words, as shown in FIG. 6D, the two ceramicssintered bodies 21 are coupled with the joint portion 4 formed by thereaction-sintering of the porous layer 23 to produce the ceramicscomposite member 1.

The carbon powder and the carbon component derived from the organicresin present in the porous layer 23 react in contact with the melted Siat a high temperature to produce silicon carbide (second SiC particles 5b). The silicon carbide powder blended into the adhesive 22 hassubstantially no grain growth and becomes the first SiC particles 5 a.The SiC particles produced by the reaction-sintering become the secondSiC particles 5 b having an average particle diameter smaller than thatof the first SiC particles 5 a based on the silicon carbide powder whichare blended as an aggregate into the adhesive 22. Besides, the Si whichwas not involved in the reaction is continuously present as the free Siphase 6 in the network form in the interstices of the first and secondSiC particles 5 a, 5 b.

By applying the above-described bonding process, the two ceramicssintered bodies 21 can be coupled by the joint portion 4 formed with thesilicon-silicon carbide composite material which includes the SiCparticles 5 having an average particle diameter of 0.1 μm or more and0.1 mm or less, and the free Si phase continuously provided in networkform in the interstices of the SiC particles 5 and having an averagediameter of 0.05 μm or more and 10 μm or less. The silicon-siliconcarbide composite material configuring the joint portion 4 has a texturewhich is composed of the first SiC particles 5 a, the second SiCparticles 5 b and the free Si phase 6 continuously provided in thenetwork form in the interstices of the SiC particles 5 a, 5 b asdescribed above.

The joint portion 4 excels in bonding strength to the ceramics sinteredbodies 21 and also excels in its own strength and reproducibility.Therefore, the two ceramics sintered bodies 21 can be joined with a highstrength, and the strength of the ceramics composite member 1 afterbonding can be enhanced with a good reproducibility. Besides, the costrequired for bonding can be reduced. Therefore, the ceramics compositemember 1 suitable for complex-shaped or large ceramic members can beprovided with a high strength at a low cost. The ceramics compositemember 1 can be applied as a various types of parts and members.

Then, the second coupling method (bonding method) will be described indetail with reference to FIG. 7A through FIG. 7D. As shown in FIG. 7A,shaped bodies 24 containing silicon carbide powder and carbon powder areprepared. The shaped bodies 24 may be applied to each of twoto-be-bonded members (ceramic members 2, 3). One of two to-be-bondedmembers may be the ceramics sintered body 21 in the same way as in thefirst method.

FIG. 7A shows a state that the shaped bodies 24 are applied to the twoto-be-bonded members. The shaped bodies 24 become a silicon-siliconcarbide composite sintered body by reaction-sintering. In a case wherethe ceramics sintered body is applied to one of the to-be-bondedmembers, its type is not particularly limited. The ceramics sinteredbody is not limited to a silicon carbide sintered body or asilicon-silicon carbide composite sintered body but may be a nitridebased or oxide based ceramics sintered body.

For example, the shaped bodies 24 are produced as follows. First,silicon carbide powder and carbon powder are mixed at a prescribedratio. It is desirable that the compounding ratio of the silicon carbidepowder and the carbon powder is in a range of 10:1 to 10:10 in massratio. If the amount of the carbon powder is smaller than the aboverange, the produced amount of SiC decreases, the size of the free Siphase increases, and the strength of the silicon-silicon carbidecomposite sintered body might be degraded. Meanwhile, if the amount ofthe carbon powder is excessively large, the volume expansion amountincreases at the time of reaction-sintering, and cracks tend to beproduced locally. In such a case, the strength might be degraded. Aknown organic binder may be added to the mixture powder if necessary.

Then, the mixture powder of the silicon carbide powder and the carbonpowder is formed into shaped bodies having a desired shape by pressforming. As a press forming method, powder pressing, press casting orthe like can be applied. In a case where the powder pressing is applied,the pressure is preferably in a range of 0.5 to 2 MPa. For the pressforming of powder, die pressing, rubber pressing, cold isotropicpressing or the like is applied. In a case where the press casting isapplied, it is desirable that the mixture powder is dispersed into wateror an organic solvent to prepare a slurry, and the slurry is subjectedto casting under a pressure of 0.5 to 10 MPa. The application of thepress forming provides shaped bodies having an appropriate density(filled state of the powder).

Thus, the two shaped bodies 24 are prepared as the to-be-bonded members.Otherwise, the shaped body 24 is prepared as one of the two to-be-bondedmembers. In such a case, a ceramics sintered body is prepared as theother. And, the two shaped bodies 24 (or the shaped body 24 and theceramics sintered body 21) are adhered with the adhesive 22 containingthe silicon carbide powder and the organic resin, and the adhesive 22also containing the carbon powder as shown in FIG. 7A. It is preferablethat the adhesive 22 is configured in the same manner as the firstmethod. It is also preferable that the adhered surfaces are treated inthe same manner as the first method.

As shown in FIG. 7B, the adhesive layer 22 is subjected to the heattreatment in the same manner as the first method to form the porouslayer 23. Thus, the two shaped bodies 24 are temporarily coupled withthe porous layer 23 to produce a preliminary coupling member 25. And, asshown in FIG. 7C, the preliminary coupling member 25 is heated to atemperature of the melting point or more of Si, and the preliminarycoupling member 25 in the heated state is entirely impregnated with themelted Si. In a case where one of the to-be-bonded members is a ceramicssintered body, the shaped bodies 24 and the porous layer 23 areimpregnated with the melted Si. The melted Si impregnation step isperformed in the same manner as the above-described first method.

In the melted Si impregnation step, the two shaped bodies 24 arerespectively subjected to reaction-sintering to form silicon-siliconcarbide composite sintered bodies 26, and the porous layer 23 is alsosubjected to the reaction-sintering to form a joint portion 4. In otherwords, the ceramics composite member 1 is produced by integrating thetwo silicon-silicon carbide composite sintered bodies 26 undergone thereaction-sintering with the joint portion 4 also undergone thereaction-sintering at the same time as shown in FIG. 7D.

The carbon powder contained in the shaped bodies 24 reacts with themelted Si at a high temperature to produce silicon carbide. At the sametime, the carbon powder contained in the porous layer 23 and the carboncomponent derived from the organic resin react with the melted Si at ahigh temperature to produce silicon carbide. Besides, thesilicon-silicon carbide composite sintered bodies 26 and the jointportion 4 having a structure in which the free Si phase is continuouslypresent in a network form among the silicon carbide particles can beobtained. When the joint portion 4 is formed, the two silicon-siliconcarbide composite sintered bodies 26 are joined with high strength.

Thus, the two silicon-silicon carbide composite sintered bodies 26 (orthe silicon-silicon carbide composite sintered body 26 and the otherceramics sintered body 21) can be coupled by the joint portion 4 whichincludes the SiC particles having an average particle diameter of 0.1 μmor more and 0.1 mm or less, and the free Si phase continuously providedin a net-like form in the interstices of the SiC particles and having anaverage diameter of 0.05 μm or more and 10 μm or less. As describedabove, the joint portion 4 has a texture which is comprised of the firstSiC particles 5 a based on the silicon carbide powder blended into theadhesive 22, the second SiC particles 5 b which are produced by reactingthe melted Si with the carbon powder blended into the adhesive 22 andthe carbon derived from the organic resin, and the free Si phase 6continuously provided in the network form in the interstices of the SiCparticles 5 a, 5 b.

The joint portion 4 excels in bonding strength to the silicon-siliconcarbide composite sintered body 26 and also excels in its own strengthand reproducibility. Besides, the bonding strength between thesilicon-silicon carbide composite sintered body 26 and the joint portion4 is further improved by reaction-sintering at the same time. Thus, thetwo ceramic members 2, 3 can be bonded with high strength, and thestrength of the ceramics composite member 1 after bonding can beimproved with a good reproducibility. In addition, the cost required forbonding can be reduced. Therefore, the ceramics composite member 1suitable for complex-shaped or large ceramic members can be providedwith high strength at a low cost. The ceramics composite member 1 can beapplied as various types of parts and members.

Then, specific examples of the invention and the evaluated results willbe described.

EXAMPLE 1

Silicon carbide powder having an average particle diameter of 0.5 μm andcarbon powder (carbon black) having an average particle diameter of 0.01μm were mixed at a mass ratio of 10:3 (=SiC:C). The mixture powder wasmixed with an appropriate amount of an organic binder, and the mixturewas dispersed into a solvent to prepare a slurry. The slurry was chargedinto a forming die under a pressure of 1 MPa by a pressure castingmachine. Thus, two plate-like shaped bodies having a prescribed shapedbody density were produced.

Then, the two plate-like shaped bodies were air dried and adhered withan adhesive. As the adhesive, a mixture of a phenol resin with siliconcarbide powder having an average particle diameter of 0.1 μm and carbonpowder (carbon black) having an average particle diameter of 0.08 μm wasused. The ratio between the silicon carbide powder and the carboncomponent derived from the carbon powder and the phenol resin wasdetermined to be SiC:C=25:75. The adhered material was heated and keptat a temperature of 500° C. in an inert gas atmosphere to change theadhesive layer to a porous layer. A preliminary coupling member havingthe two plate-like shaped bodies coupled with the porous layer washeated to a temperature of 1400° C. or more under reduced pressure or inan inert gas atmosphere, and the shaped bodies and the porous layer keptin the heated state were impregnated with the melted silicon.

In the melted silicon impregnation step, the two plate-like shapedbodies were subjected to reaction-sintering to produce an Si—SiCcomposite sintered body, and also a ceramics composite member wasobtained by coupling them with a joint portion formed byreaction-sintering. The joint portion had a thickness of about 5 μm anda porosity of less than 1%. Besides, each surface of the joint portionwas polished and its microstructure was observed with an electronmicroscope. It was confirmed that the joint portion had the texture inwhich the free Si phase was continuously provided in the network form inthe interstices of the SiC particles. The joint portion had a singlelayer structure. The SiC particles had an average particle diameter of0.1 μm. The free Si phase had an average diameter of 0.05 μm, and itscontent (composition ratio) was 10 mass %. The obtained ceramicscomposite member was subjected to the characteristic evaluation to bedescribed later.

EXAMPLE 2

Two shaped bodies produced in the same manner as in Example 1 describedabove were heated and kept at a temperature of 600° C. in an inert gasatmosphere to remove (degrease) the organic binder. The degreased shapedbodies were heated to a temperature of 1400° C. or more under reducedpressure or in an inert gas atmosphere, and the shaped bodies kept inthe heated state were impregnated with melted silicon. In the meltedsilicon impregnation step, the shaped bodies were subjected toreaction-sintering to obtain two Si—SiC composite sintered bodies.

Then, the adhered surfaces of the two SiC radical reaction sinteredbodies were subjected to a blast treatment and adhered with an adhesive.As the adhesive, a mixture of a phenol resin with silicon carbide powderhaving an average particle diameter of 1 μm and carbon powder (carbonblack) having an average particle diameter of 0.8 μm was used. The ratiobetween the silicon carbide powder and the carbon component derived fromthe carbon powder and the phenol resin was determined to be SiC:C=30:70.The adhered material was heated and kept at a temperature of 500° C. inan inert gas atmosphere to change the adhesive layer to a porous layer.A preliminary coupling member having the two sintered bodies coupledwith the porous layer was heated to a temperature of 1400° C. or moreunder reduced pressure or in an inert gas atmosphere, and the porouslayer kept in the heated state was impregnated with the melted silicon.

In the melted silicon impregnation step, a ceramics composite memberhaving the two Si—SiC composite sintered bodies coupled with a jointportion formed by reaction-sintering was produced. The joint portion hada thickness of about 20 μm and a porosity of 3%. Besides, the surfacesof the joint portion were polished and its microstructure was observedwith an electron microscope. It was confirmed that the joint portion hadthe texture in which the free Si phase was continuously provided in thenetwork form in the interstices of the SiC particles. The joint portionhad a single layer structure. The SiC particles had an average particlediameter of 10 μm. The free Si phase had an average diameter of 0.1 μm,and its content was 30 mass %. The obtained ceramics composite memberwas subjected to the characteristic evaluation to be described later.

EXAMPLES 3 TO 10

As to-be-bonded members, an Si—SiC composite sintered body, shapedbodies for Si—SiC composite body, an ordinary SiC sintered body, anSi₃N₄ sintered body, a ZrO₂ sintered body and an SiC-continuous fibercomposite material were prepared. They were coupled according to thecombinations shown in Table 1 to produce ceramics composite members. Thecoupling step was performed in the same manner as in Examples 1 and 2.The adhesives used for coupling had the compositions as shown inTable 1. Table 1 also shows the properties of the joint portions. Thejoint portions of the ceramics composite members had the texture inwhich the free Si phase is continuously provided in the network form inthe interstices of the SiC particles, and also had the single layerstructure. The individual ceramics composite members were subjected tothe characteristic evaluation to be described later.

COMPARATIVE EXAMPLE 1

Two shaped bodies produced in the same manner as in Example 1 weremutually bonded with a silicon sheet held between them to produce apreliminary coupling member. The preliminary coupling member wasimpregnated with melted silicon in the same conditions as in Example 1.The obtained ceramics composite member was subjected to thecharacteristic evaluation to be described later.

COMPARATIVE EXAMPLE 2

Two shaped bodies produced in the same manner as in Example 1 weremutually adhered with polycarbosilane to produce a preliminary couplingmember. The preliminary coupling member was impregnated with meltedsilicon in the same conditions as in Example 1. The obtained ceramicscomposite member was subjected to the characteristic evaluation to bedescribed later.

COMPARATIVE EXAMPLE 3

Two shaped bodies produced in the same manner as in Example 1 weremutually adhered with a slurry, which was prepared by dispersing siliconcarbide powder and carbon powder into a solvent, to produce apreliminary coupling member. The preliminary coupling member wasimpregnated with melted silicon in the same conditions as in Example 1.The obtained ceramics composite member was subjected to thecharacteristic evaluation to be described later.

TABLE 1 Adhesive SiC:C To-be-bonded To-be-bonded (mass Organic member 1member 2 ratio) resin E1 Shaped body for Shaped body for 25:75 PhenolSi—SiC composite Si—SiC composite body body E2 Si—SiC composite Si—SiCcomposite 30:70 Polyimide sintered body sintered body E3 SiC sinteredbody SiC sintered body 25:75 Phenol E4 Si₃N₄ sintered Si₃N₄ sintered30:70 Epoxy body body E5 SiC-continuous SiC-continuous 25:70 Polyimidefiber composite fiber composite material material E6 ZrO₂ sintered bodyZrO₂ sintered body 30:70 Epoxy E7 Shaped body for Shaped body for 75:25Epoxy Si—SiC composite Si—SiC composite body body E8 Shaped body forShaped body for 30:70 Polyimide Si—SiC composite Si—SiC composite bodybody E9 Shaped body for Shaped body for 75:25 Epoxy Si—SiC compositeSi—SiC composite body body E10 Shaped body for Shaped body for 60:40Phenol Si—SiC composite Si—SiC composite body body CE1 Shaped body forShaped body for (Silicon sheet) Si—SiC composite Si—SiC composite bodybody CE2 Shaped body for Shaped body for (Polycarbosilane) Si—SiCcomposite Si—SiC composite body body CE3 Shaped body for Shaped body for70:30 (Slurry) Si—SiC composite Si—SiC composite body body E1 = Example1; E2 = Example 2; E3 = Example 3; E4 = Example 4; E5 = Example 5; E6 =Example 6; E7 = Example 7; E8 = Example 8; E9 = Example 9; E10 = Example10, CE1 = Comparative Example 1; CE2 = Comparative Example 2; CE3 =Comparative Example 3

The individual ceramics composite members according to Examples 1 to 10and Comparative Examples 1 to 3 described above were measured formechanical properties and thermal properties as follows. First, testpieces prepared from the joint portions which were mirror finished andwhose microstructures were observed were used to measure the jointportions for a Vickers hardness. The results are shown in Table 2. TheVickers hardness is an average value of the individual examples.

Then, bending test pieces each having a width of 4 mm, a thickness of 3mm and a length of 40 mm were produced from the individual ceramicscomposite members by machining. At that time, it was determined that thejoint portion was perpendicular to the longitudinal direction of thetest piece and positioned at the center of the test piece. Such bendingtest pieces were used to perform a four-point bending test (roomtemperature) under conditions of a span of 30 mm and a head speed of 0.5mm/min. The results are shown in Table 2. The measured result by thebending test is an average value of the individual examples.

Besides, test pieces each having a diameter of 10 mm and a thickness of2 mm for measurement of heat conductivity were produced from theindividual ceramics composite members by machining. At that time, it wasdetermined that the joint portion was parallel to the surface having adiameter of 10 mm and positioned at the center of the test piece. Suchtest pieces for measurement of heat conductivity were used to measurethe heat conductivity at room temperature according to the method fortesting the thermal diffusivity, specific heat capacity and thermalconductivity of fine ceramics by laser flash process (JIS R 1611). Atthe same time, the individual substrates were also measured for the heatconductivity. From the results, the heat conductivity of the jointportion was determined by calculating. The results are shown in Table 2.

TABLE 2 Joint portion Average Average Heat particle diameter CompositionHardness conductivity diameter of of Si ratio of of joint Bending ofjoint Thickness Porosity SiC particles phase Si phase portion strengthportion (μm) (%) (μm) (μm) (mass %) (Hv) (MPa) (W/m · K) E1 5 >1 0.10.05 10 2200 1400 150 E2 20 3 1 0.1 30 1700 900 130 E3 50 3 10 1 50 1300500 110 E4 500 3 100 10 70 1000 350 90 E5 40 3 5 0.5 25 1800 650 140 E6200 3 50 10 50 1300 400 110 E7 500 2 200 15 50 1600 400 130 E8 1000 2 100.1 30 1600 400 130 E9 40 9 10 0.1 30 1600 350 90 E10 40 2 10 0.1 85 900350 90 CE1 200 2 — — 100 700 120 60 CE2 200 20 10 — 0 1600 180 30 CE3200 5 10 — 50 1600 200 70 E1 = Example 1; E2 = Example 2; E3 = Example3; E4 = Example 4; E5 = Example 5; E6 = Example 6; E7 = Example 7; E8 =Example 8; E9 = Example 9; E10 = Example 10, CE1 = Comparative Example1; CE2 = Comparative Example 2; CE3 = Comparative Example 3

It is apparent from Table 2 that the ceramics composite members ofExamples 1 to 10 had a Vickers hardness of HV900 to 2200, a four-pointbending strength of 350 to 1400 MPa, and heat conductivity of 90 to 150W/mK. It is seen that the ceramics composite members of Examples 1 to 10have the joint portions excelling in mechanical properties and thermalproperties in comparison with Comparative Examples 1 to 3. When it isdetermined that the microstructure of the joint portion has the texturein which the free Si phase is continuously provided in the network formin the interstices of the SiC particles, and the SiC particles have anaverage particle diameter of 0.1 to 100 μm and the free Si phase has anaverage diameter of 0.05 to 10 μm, the ceramics composite members havingthe joint portion with excellent strength and heat conductivity can beobtained.

EXAMPLES 11 TO 18

Silicon carbide powder having an average particle diameter of 0.5 μm andcarbon powder (carbon black) having an average particle diameter of 0.01μm were mixed at a mass ratio of 10:3 (=SiC:C). Besides, the mixturepowder was mixed with an appropriate amount of an organic binder, andthe obtained mixture was dispersed into a solvent to prepare a slurry.The slurry was charged into a forming die under a pressure of 1 MPa by apressure casting machine. Thus, one plate-like shaped body having aprescribed shaped body density was produced.

Then, as members to be bonded to the above-described plate-like shapedbody, an Si—SiC composite sintered body, an SiC-continuous fibercomposite material, an ordinary SiC sintered body, an Si₃N₄ sinteredbody and a ZrO₂ sintered body were prepared. The adhered surfaces of theindividual to-be-bonded members were subjected to a blast treatment oran etching treatment with chemicals. The individual adhered surfaces hada surface roughness (Ra) of 1 to 10 μm. Then, the to-be-bonded memberswere adhered with the adhesives shown in Table 3. The adhered memberswere heated and kept at a temperature of 100 to 700° C. in an inert gasatmosphere to change the adhesive layers to porous layers. The porouslayers had a porosity of 30 to 60%.

A preliminary coupling member having the to-be-bonded members coupledwith the above-described porous layer was heated to a temperature of1400° C. or more under reduced pressure or in an inert gas atmosphere.The shaped bodies and the porous layer kept in the heated state wereimpregnated with the melted silicon. The joint portion of the individualceramics composite members obtained as described above had a texture inwhich the free Si phase was continuously provided in a net-like formamong the SiC particles. The joint portions had a laminated structurewith a different content of the Si phase. The properties of such jointportions are shown in Table 4. The mechanical properties and thermalproperties of the individual ceramics composite members were measured inthe same manner as in Example 1. The results are shown in Table 5.

TABLE 3 Adhesive SiC:C To-be-bonded To-be-bonded (mass Organic member 1member 2 ratio) resin E11 Shaped body for Si—SiC composite 25:75Polyimide Si—SiC composite sintered body body E12 Shaped body forSiC-continuous 30:70 Epoxy Si—SiC composite fiber composite bodymaterial E13 Shaped body for SiC sintered body 25:75 Phenol Si—SiCcomposite body E14 Shaped body for Si₃N₄ sintered 30:70 Polyimide Si—SiCcomposite body body E15 Shaped body for ZrO₂ sintered body 25:70 EpoxySi—SiC composite body E16 Shaped body for Shaped body for 30:70 PhenolSi—SiC composite Si—SiC composite body body E17 Shaped body for Shapedbody for 25:75 Polyimide Si—SiC composite Si—SiC composite body body E18Shaped body for Shaped body for 30:70 Phenol Si—SiC composite Si—SiCcomposite body body E11 = Example 11; E12 = Example 12; E13 = Example13; E14 = Example 14; E15 = Example 15; E16 = Example 16; E17 = Example17; E18 = Example 18

TABLE 4 Joint portion Intermediate (whole laminated structure) layer ofAverage joint portion particle Average Composition Composition diameterdiameter ratio ratio of SiC of Si of Si of Si Thickness Porosityparticles phase phase Thickness phase (μm) (%) (μm) (μm) (mass %) (μm)(mass %) E11 40 2 5 0.2 25 30 40 E12 200 2 50 5 50 100 60 E13 40 2 5 0.125 30 40 E14 200 2 50 5 50 100 60 E15 40 2 5 0.2 25 30 40 E16 20 >1 10.08 30 10 60 E17 40 >1 10 1 30 30 40 E18 200 >1 100 0.1 30 100 60 E11 =Example 11; E12 = Example 12; E13 = Example 13; E14 = Example 14; E15 =Example 15; E16 = Example 16; E17 = Example 17; E18 = Example 18

TABLE 5 Hardness of Bending Heat conductivity joint portion strength ofjoint portion (Hv) (Mpa) (W/m · K) Example 11 1700 900 130 Example 121200 650 — Example 13 1700 700 — Example 14 1200 500 — Example 15 1700600 — Example 16 1600 1200 130 Example 17 1600 1000 130 Example 18 1600800 130

It is apparent from Table 4 and Table 5 that the mechanical propertiesand thermal properties of the ceramics composite member can be furtherimproved by forming the joint portion to have a laminated structurehaving an intermediate layer with a high Si composition ratio andcontrolling the thickness of the intermediate layer and the Sicomposition ratio at that time.

1. A ceramics composite member, comprising: a first ceramic member; asecond ceramic member; and a joint portion which couples the firstceramic member and the second ceramic member and has a texture includingsilicon carbide particles, which have an average particle diameter of0.1 μm or more and 0.1 mm or less, and a silicon phase, which iscontinuously provided in network form in interstices of the siliconcarbide particles and has an average diameter of 0.05 μm or more and 10μm or less.
 2. The ceramics composite member according to claim 1,wherein the first and second ceramic members are composed of the same ordifferent kinds of ceramics sintered bodies selected from carbide,nitride, oxide, boride, silicide and their composites.
 3. The ceramicscomposite member according to claim 1, wherein at least one of the firstand second ceramic members is composed of a silicon carbide sinteredbody or a silicon-silicon carbide composite sintered body.
 4. Theceramics composite member according to claim 1, wherein the jointportion contains the silicon phase in a range of 5 mass % or more and 85mass % or less.
 5. The ceramics composite member according to claim 1,wherein the joint portion has an average thickness in a range of 5 μm ormore and 5 mm or less.
 6. The ceramics composite member according toclaim 1, wherein the joint portion has a porosity of 5% or less.
 7. Theceramics composite member according to claim 1, wherein the jointportion is composed of a reaction-sintering layer which is formed byimpregnating an adhesive layer containing at least silicon carbidepowder and an organic resin with melted silicon.
 8. The ceramicscomposite member according to claim 7, wherein the adhesive layerfurther contains carbon powder.
 9. The ceramics composite memberaccording to claim 8, wherein the silicon carbide particles configuringthe joint portion include first silicon carbide particles, which arebased on the silicon carbide powder blended as an aggregate into theadhesive layer, and second silicon carbide particles, which are producedby a reaction between the melted silicon and carbon derived from thecarbon powder and the organic resin blended into the adhesive layer. 10.The ceramics composite member according to claim 1, wherein the jointportion has a structure in which plural layers each having the Si phasein a different content are laminated.
 11. The ceramics composite memberaccording to claim 10, wherein the joint portion includes a first sidelayer which is in contact with the first ceramic member, a second sidelayer which is in contact with the second ceramic member, and anintermediate layer which is disposed between the first side layer andthe second side layer and contains the Si phase in an amount larger thanin the first and second side layers.
 12. The ceramics composite memberaccording to claim 1, wherein the joint portion has hardness of Hv900 ormore and Hv2200 or less in terms of a Vickers hardness.
 13. The ceramicscomposite member according to claim 1, wherein the ceramics compositemember has a four-point bending strength of 250 MPa or more and 1400 MPaor less.
 14. A method of producing a ceramics composite member,comprising: adhering a first ceramic member and a second ceramic memberwith an adhesive containing at least silicon carbide powder and anorganic resin; heat-treating a bonding portion based on the adhesive tocarbonize the adhesive; and impregnating the bonding portion with meltedsilicon to couple the first ceramic member and the second ceramic memberwith a joint portion which is formed by reaction-sintering the bondingportion.
 15. The method of producing the ceramics composite memberaccording to claim 14, wherein the adhesive further contains carbonpowder.
 16. The method of producing the ceramics composite memberaccording to claim 15, wherein a mass ratio of the silicon carbidepowder and carbon derived from the carbon powder and the organic resinin the adhesive is in a range of SiC:C=5 to 80:95 to
 20. 17. The methodof producing the ceramics composite member according to claim 15,wherein the joint portion has a texture including silicon carbideparticles, which have an average particle diameter in a range of 0.1 μmor more and 0.1 mm or less, and a silicon phase, which is continuouslyprovided in a network form in interstices of the silicon carbideparticles and has an average diameter of 0.05 μm or more and 10 μm orless.
 18. The method of producing the ceramics composite memberaccording to claim 17, wherein the silicon carbide particles configuringthe joint portion include first silicon carbide particles, which arebased on the silicon carbide powder contained in the adhesive, andsecond silicon carbide particles, which are produced by a reactionbetween the melted silicon and carbon derived from the carbon powder andthe organic resin contained in the adhesive.
 19. The method of producingthe ceramics composite member according to claim 14, wherein the firstand second ceramic members are composed of the same or different kindsof ceramics sintered bodies selected from carbide, nitride, oxide,boride, silicide and their composites.
 20. The method of producing theceramics composite member according to claim 14, further comprising:performing a blast treatment or an etching treatment on the adheredsurfaces of the ceramic members.
 21. A method of producing a ceramicscomposite member, comprising: adhering shaped bodies each containingsilicon carbide powder and carbon powder or the shaped body and aceramics sintered body with an adhesive containing at least siliconcarbide powder and an organic resin; heat-treating a bonding portionbased on the adhesive to carbonize the adhesive; and impregnating theshaped bodies and the bonding portion with melted silicon to couplesilicon-silicon carbide composite sintered bodies which are formed byreaction-sintering the shaped bodies or the silicon-silicon carbidecomposite sintered body and the ceramics sintered body with a jointportion which is formed by reaction-sintering the bonding portion. 22.The method of producing the ceramics composite member according to claim21, wherein the adhesive further contains carbon powder.
 23. The methodof producing the ceramics composite member according to claim 22,wherein a mass ratio of the silicon carbide powder and carbon derivedfrom the carbon powder and the organic resin in the adhesive is in arange of SiC:C=5 to 80:95 to
 20. 24. The method of producing theceramics composite member according to claim 22, wherein the jointportion has a texture including silicon carbide particles, which have anaverage particle diameter in a range of 0.1 μm or more and 0.1 mm orless, and a silicon phase, which is continuously provided in a networkform in interstices of the silicon carbide particles and has an averagediameter of 0.05 μm or more and 10 μm or less.
 25. The method ofproducing the ceramics composite member according to claim 24, whereinthe silicon carbide particles configuring the joint portion includefirst silicon carbide particles, which are based on the silicon carbidepowder contained in the adhesive, and second silicon carbide particles,which are produced by a reaction between the melted silicon and carbonderived from the carbon powder and the organic resin contained in theadhesive.
 26. The method of producing the ceramics composite memberaccording to claim 21, wherein the ceramics sintered body is composed ofcarbide, nitride, oxide, boride, silicide or their composites.